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Cellulose paper, a material that is naturally derived, low cost, lightweight, eco-friendly, and mechanically deformable, plays important roles in producing next-generation flexible electronics. Following the booms in the development of functional electronics, the soft actuators built from cellulose paper have attracted great attention. In this focused review, the milestones and recent achievements of cellulose paper-based actuators are summarized. Electro-, thermal, moisture and magnetic actuation mechanisms are utilized to acquire energy from external stimuli. Corresponding functional materials and available fabrication techniques like film assembly and layer deposition are described. Programmable actions for the emerging applications in bionics, paper grippers and robots are realized by pursuing different strategies to control the responding deformation. Along with a conclusion, the existing challenges and possible solutions in evaluating and improving the performance of cellulose paper are summarized in the final section.

Water-activated paper-based batteries are expected to be low-cost disposable power sources for paper-based sensor applications. In this study, a disposable paper-based battery was developed. The battery used activated carbon powder loaded on a carbon sheet as the anode. The cathode was coated directly on a paper filter to fabricate an integrated proton exchange membrane cathode. Copper (II) chloride mixed with multiwalled carbon nanotube (CuCl2/CNT) was used as the cathode. Water was injected into the anode electrode to activate the battery. The maximum power density of 134. 6 μ W /cm2 was obtained with the anode loaded 17 mg cm−2 activated carbon powder. The power output of the battery is proportional to the amount of activated carbon loaded on the anode.

As a new type of energy harvesting device, the triboelectric nanogenerator (TENG) can convert mechanical energy into electrical energy effectively. Paper-based materials have gained considerable attention for use in flexible energy harvesting device applications because of their flexibility, environmental friendliness (i.e., they are biodegradable and renewable), and foldability. This work proposes a strategy to use cellulose fibers layer as a spacer of paper-based triboelectric nanogenerator (P-TENG). The P-TENG consists of a three-layer fiber material and a copper electrode. The three-layer fiber material comprises nylon, cellulose, and polypropylene, where the cellulose fiber layer contains millimeter-sized holes and is used as a spacer. Because of its attractive cuttability and flexibility properties, the P-TENG can be applied on a large scale in complex environments (e.g., sports fields, driving training fields) to detect signal changes caused by external pressure This type of device has great potential for application to the large-scale TENG field and may provide a new solution for TENG industrialization.

Bulk graphitic carbon materials with expanded interlayer spacing and abundant defects may serve as efficient anodes with high areal capacities for sodium-ion batteries (SIBs). However, obtaining long-range order in bulk graphitic carbon materials with expanded interlayer spacing is extremely difficult. Herein, an explosive decomposition method is demonstrated to realize thermally reduced graphene oxide (rGO) paper with tuned interlayer spacing. The in-situ temperature-dependent X-ray diffraction (td-XRD) was utilized to establish the correlation between heating rate and interlayer spacing. Based on td-XRD results, free-standing graphene paper (FSG) was synthesized at 450°C under a high heating rate of 70°C/min. The FSG exhibits a highly porous structure made of graphene flakes with abundant surface epoxy groups with an overall interlayer spacing of 0.38–0.39 nm. The rGO flakes in FSG are separated by large voids that provide fast mass transport pathways and allow expansion/contraction of crystallites upon reversible Na intercalation. The FSG was utilized directly as anodes without any binder and conductive agent and delivered an excellent reversible capacity of 290 mAh/g at a current density of 50 mA/g. Moreover, the FSG exhibited excellent foldability and rollability to create high areal density anodes, delivering an areal capacity of 0.62 mAh/cm2 at a current density of 100 μA/cm2. These results open the door to fabricate graphene material-based carbon anodes with tunable interlayer spacing for high-performance SIBs.

To study the influence of different concentrations of zinc oxide (ZnO)/silicon dioxide (SiO2) composite coating on hydrophobic property and mechanical stability of paper mulch film, three kinds of ZnO/SiO2 composite coating paper mulch films (2%, 4%, 6%) with different coating substance contents were prepared by brush coating method. Through particle size analysis, contact angle, rolling angle and mechanical stability test, combined with scanning electron microscope, three-dimensional morphology and roughness measuring instrument, the optimal concentration of ZnO/SiO2 composite coated paper mulch film was screened out. Through acid-base salt corrosion test, silver mirror reaction and surface self-cleaning, the optimal concentration of composite coated paper mulch film was compared with the original paper mulch film to prove its excellent chemical stability and hydrophobicity. The results show that the paper mulch film with 4% coating material has excellent hydrophobicity and mechanical stability, can effectively reduce the surface roughness of paper mulch film, and has remarkable effects in resisting acid, alkali and salt and self-cleaning.

This study's focus was to develop a potential pathway for recycling of the paper mill sludge compost (PMSC) in brick making. Composting reduces the paper mill sludge (PMS) moisture content considerably and shredding becomes easier. The addition of PMSC leads to an increase of porosities in bricks and makes them lighter, besides delivering energy to the firing process from burning organics. Lighter construction materials help minimize construction outlay by reducing labour and transportation costs and lesser expense on foundation construction. The variability in the experimental data and the brick properties were investigated for two types of soils, typical in the brick industry of India (alluvial and laterite soil), blended with PMSC in five mix ratios (0%, 5%, 10%, 15% and 20%). The samples of oven-dried bricks were fired at two different temperatures (850 and 900 °C) in an electrically operated muffle furnace representing typical conditions of a brick kiln. Various properties of bricks were analyzed which included linear shrinkage, bulk density, water absorption and compressive strength. Conclusions were drawn based on these properties. It was found that the addition of PMSC to the alluvial and laterite soil by up to 10% weight yield mechanical properties of fired bricks compliant with the relevant Indian and ASTM codes. Toxicity characteristic leaching procedure (TCLP) tests showed that PMSC incorporated fired bricks are safe to use in regular applications as non-load-bearing and infill walls. This study is timely in light of the European Green Deal putting focus on circular economy. Besides, it fulfills the objective of UN sustainable development goals (SDG). © 2021 Elsevier Ltd

The pulp and paper industry has been researching different treatments for the degradation of adsorbable organohalogens (AOX). In this work, two agitation processes (mechanical and ultrasound) were analyzed in the AOX degradation of the bleaching wastewater using nano zero valent iron (nZVI). The work used different variables for the AOX removal process, such as pH, time, nZVI, and hydrogen peroxide (H 2 O2) concentration. Results show an increase in AOX degradation when a higher nZVI concentration is used. The optimal combination of variables for the treatment with mechanical agitation was found in the ratio 2:5 (nZVI : H 2 O2), degrading 85% of AOX in 60 min, with acid pH. Ultrasound treatment consisted of half process time and less degradation than mechanical agitation treatment. The 2:5 ratio in ultrasound agitation degraded 55% of AOX within 30 min at the end of the process. Both methods of the homogenization process of zero valent iron nanoparticles in the bleaching wastewater of the paper and cellulose industry are efficient. However, the mechanical stirring process has a more significant potential for AOX degradation. The variables (pH, concentration of nZVI and H 2 O2 and duration of the process) used in the bleaching wastewater treatment process must be considered for future implementation in the pulp and paper industry.

Detection of mycotoxins by conventional methods such as ELISA or LC-MS can be expensive and time-consuming. Therefore, paper-based biosensors can be effectively used for on-site analysis, due to their low cost and easy detection procedures. Nevertheless, even when the application of colorimetric methods on paper enhance the simplicity and affordability of multiple determinations, the signal intensity and final readout can be affected by a limited color uniformity. In this work, Ellman’s method for the quantification of aflatoxin B1 was utilized as a model colorimetric assay on paper, in which the test zones were modified with chitosan-immobilized enzyme (AChE). A comparison of the cross-linking effect of genipin on two chitosans of varying molar mass and degree of acetylation, exhibited a greater signal enhancement from the sample with a higher degree of acetylation and molecular weight.

The transwell assay is currently the most popular approach to studying cellular invasion due to its ease of use and readout, and the possibility for quantitative measurements. However, it only allows end-point measurements without the possibility for real-time tracking of the dynamics of cell movement during an invasion. Moreover, it requires cell labeling, and construction of customized devices is hampered by the commercial standard membrane inserts, only available in certain designs. Recently, paper has been used as a scaffold for three-dimensional (3D) cell cultures. Because of its microfibrous structure and easy handling, it could be a versatile alternative as a membrane insert in customized devices. Here, we develop a low-cost real-time invasion assay device using paper as an alternative membrane insert. The device was designed for two-electrode impedance measurements and fabricated using CNC micromilling. It also comprised a disposable low-cost stencil-printed working electrode on a poly(methyl methacrylate) substrate below the membrane and glassy carbon counter electrode above the membrane inserted in a specially designed lid. Thus, the impedance measurements during cell invasion addressed the entire membrane. We demonstrated the function of the device by monitoring the invasion of B16 melanoma 4A5 cells from a mouse using insulin growth factor-1 as the chemoattractant. The cell invasion on paper was visualized using scanning electron microscopy and confocal microscopy with Z-stack 3D imaging. Melanoma cell invasion could be observed within 7 h after the chemoattractant treatment, which was faster than the conventional assay and less likely to be influenced by cell proliferation.

ATP-driven bioluminescence relying on the D-luciferin-luciferase reaction is widely employed for several biosensing applications where bacterial ATP detection allows to verify microbial contamination for hygiene monitoring in hospitals, food processing and in general for cell viability studies. Several ATP kit assays are already commercially available but an user-friendly ATP biosensor characterized by low-cost, portability, and adequate sensitivity would be highly valuable for rapid and facile on site screening. Thanks to an innovative freeze-drying procedure, we developed a user-friendly, ready-to-use and stable ATP sensing paper biosensor that can be combined with smartphone detection. The ATP sensing paper includes a lyophilized “nano-lantern” with reaction components being rapidly reconstituted by 10 μL sample addition, enabling detection of 10−14 mol of ATP within 10 min. We analysed urinary microbial ATP as a biomarker of urinary tract infection (UTI), confirming the capability of the ATP sensing paper to detect the threshold for positivity corresponding to 105 colony-forming units of bacteria per mL of urin, This research was sponsored in part by PRIN 2015 “Multifunctional nanotools for advanced cancer diagnostics” (Prot. 2015TWP83Z) and the NATO Science for Peace and Security Programme under Grant No. 985042. The ICN2 is funded by the CERCA Programme/Generalitat de Catalunya and also supported by the Severo Ochoa program of the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, grants No. SEV-2017-0706 and MAT2017-87202-P).

Among the largest producers of waste, the paper industry stands out due to its impact on human health and ecological balance. However, these residues may also contribute to a more environmental friendly brick industry, since the incorporation of fluxing agents may improve the firing process and the induced porosity reduces thermal conductivity of fired bricks. Therefore, this study aims to assess the feasibility of replacing clay with solid paper residue (PPR) from 2.5 to 17.5% in order to reduce resources depletion and improve brick performance. The original clay was characterized as a non-calcareous red clay with high contents of kaolinite. Several samples were made by extrusion and fired at 900 °C in accordance with industrial procedures. The addition of PPR led to increase shrinkage from 5 to 10% due to the effect of fluxing oxides which reduced pores volume and enlarged pores size. In addition, the impervious fraction was slightly reduced while the apparent porosity certainly increased (i.e. approx. 17%) due to the macroscopic pores developed by PPR combustion. This porosity produces lighter bricks (i.e. density decays from 1.76 to 1.39 g dm−3) with lower thermal conductivity (i.e. from 5.53 to 0.41 W m−1 K−1) but also reduces compressive strength (i.e. from 11 to 3 MPa) and increases water absorption (i.e. up to 24%). Nevertheless, toxicity is below the regulatory limits in all cases and fired bricks are easily adaptable to industrial procedures. It must be noticed that this work was supported by the Chilean National Commission on Research and Development (CONICYT) [grant number FONDECYT REGULAR 1180414]. Technical and human support provided by CICT of Universidad de Jaén (UJA, MINECO, Junta de Andalucía, FEDER) and by Centro de Manejo de Residuos y Energía (BIOREN) Universidad de la Frontera (Chile) are gratefully acknowledged.

© 2020 Elsevier B.V. Telomerase activity has been demonstrated in a wide variety of most solid tumors and considered as a well-known cancer biomarker. The commonly utilized method for its detection is polymerase chain reaction (PCR)-based telomeric repeat amplification protocol (TRAP). However, the TRAP technique suffers from false-negative results caused by the failure of PCR step. Moreover, it requires advanced equipment with a tedious and time-consuming procedure. Herein, we presented a portable nitrocellulose paper-based nanobiosensing platform for ultrafast and equipment-free detection of telomerase activity based on a simple colorimetric assay that enabled naked-eye visualization of the color change in response to enzyme activity. In this platform, hybridization was initially performed between telomere complementary oligonucleotide immobilized on gold nanoparticles (GNPs) and telomerase elongated biotinylated probe. Thereafter, the assembly was attached on activated paper strip via avidin-biotin interaction. The signal amplification was carried out by enlargement of the attached GNPs on the paper strip, forming tightly compact rod-shaped submicron structures of gold representing a visual color formation. Thanks to significant sensitivity enhancement, the color change was occurred for down to 6 cells, which can be easily observed by the naked eye. Due to the desired aspects of the developed assay including PCR-free, low cost, simple, and high sensitivity, it can be used for evaluation of telomerase activity in cell extracts for future clinical applications. Furthermore, this design has the ability to be easily integrated into lab-on-chip devices for point-of-care telomerase sensing.

This work presents a new optical microfluidic paper biosensor for the detection of organophosphate pesticides and carbamate pesticides. The assay strip is composed of a paper support (1 × 17.6 mm) onto which acet- ylcholine esterase (AChE) and acetylcholine chloride (AChCl) are deposited, in such a way that there is a small hole between them that ensures that they only come into contact in the reaction zone when they are carried by a solution of the sample by lateral flow to the reaction zone containing bromocresol purple (BCP) as the pH indicator, immobilized by sol-gel. The sensor operates at room temperature and the rate of the inhibited reaction serves as an analytical signal, which is measured using a camera by quantifying the appropriate colour co- ordinate. Calibration curves were obtained for chlorpyrifos and carbaryl, with a useful concentration range from 0.24 to 20 μg L−1 for carbaryl and from 2.00 to 45 μg L−1 for chlorpyrifos. The detection limits were 0.24 and 2.00 μg L−1, respectively, and with reproducibility around 4.2–5.5%. The method was applied to the de- termination of pesticides in different water samples, with no sample preparation., This study was supported by a project from the Spanish MINECO (CTQ2016-78754-C2-1-R), a project partially supported by European Regional Development Funds (ERDF).

D0bleaching wastewater from E. globulus Kraft pulping industry was treated by Fenton and photo-Fenton processes. The aim was to optimize the operational conditions for adsorbable organic halides (AOX) removal, namely oxidant concentration, [H2O2], catalyst concentration, [Fe2＋], and treatment time, using the central composite experimental design (CCED) tool. Temperature and pH were set at 60 ºC and 2, respectively, which are similar to the natural values of the D0bleaching wastewater. Both processes showed potential to remove AOX from D0with 177 - 178 mM H2O2 and 10 min reaction time. Maximum AOX removal was 85 % for the Fenton process with 8.5 mM Fe2＋, and 95 % for the photo-Fenton process with 2.0 mM Fe2＋ and UV irradiance 142 W.m− 2. For both methods, the only statistically significant variable (p=0.05) was the concentration of oxidant, [H2O2]. Keywords: AOX, Bleaching wastewater, CCED, Fenton, Photo-Fenton, Pulp and paper industry

During recent years, the socio political pressure to develop suitable technologies capable of treating wastewater from the paper and pulp industry has increased due to strict environmental regulations. System closure could potentially lead to substantial operating and discharge cost savings. This study evaluates the potential of combining an aerobic moving bed biofilm reactor (MBBR) (biological) and a Fenton-like system (advanced oxidation processes) for treating recycle mill effluent (RME). The performance of the moving bed biofilm reactor (MBBR) was evaluated at three different hydraulic residence times (HRT). The HRT used were 24, 16 and 5 h and the corresponding total chemical oxygen demand (COD) removals were 55, 49 and 43% respectively. The volatile organic acids (VOA) removals were 63.5, 58.7 and 53% respectively. The Kincannon-Stover model was used to describe the kinetic behaviour of the MBBR. The calculated KB and Umax parameters for the COD were 26.37 g.L−1.d−1 and 15.06 g.L−1.d−1 respectively. For the VOA, the KB and Umax parameters were 11.81 g.L−1.d−1 and 8.87 g.L−1.d−1. The Fenton-like experiments were carried out in batch runs. The first experiments were carried out to determine the optimal reaction parameters. Maximum COD removals were found to be at a pH of 3.33, Fe3+ dosage of 1,000 mg/L and H2O2 of 14.55 mM. Pseudo-first order reaction kinetics was used to describe the kinetic characteristics of the Fenton-like treatment system. The calculated kinetic parameters ηmax (%) and kCOD (min−1) were 53.8% and 0.112 min−1 respectively at a pH of 3.24, Fe3+ dosage of 250 mg/L and a H2O2 dosage of 77 mM. Keywords: Moving bed biofilm reactor (MBBR), Fenton-like system, Recycle mill effluent (RME)

A 4D imaging study (3D + time) combining synchrotron tomography with in situ tensile testing has been carried out to observe the fibre and network level micromechanics of paper made from northern bleached softwood kraft (NBSK). Quantitative image analysis and digital volume correlation is used to characterize local deformation, the evolution of fibre-fibre contacts, and fibre straightening in a ”freeze-dried” handsheet as well as standard handsheets low consistency refined at different refining energies. In the freeze-dried handsheet having low fibre conformability, the results show that deformation at the network level occurs because of fibre straightening and possible inter-fibre bond breakage. Further, significant out-of-plane deformation near the failure regions was observed, which led to auxetic behaviour. In the refined handsheets, a strong inverse correlation is seen between refining energy, thickness expansion, and the number of broken fibres. The use of out-of-plane strain norms is proposed as a method to determine network efficiency (i.e. the ratio of the network’s elastic modulus to that of the constituent fibres) as well as the relative contribution of fibre pull-out to the overall failure of the handsheet.

The need for a continuous, real-time monitoring of specific diseases represents an unmet scientific need. Evidently, cancer is one of the most important diseases where it is crucial to increase the rates of patient survival and monitor disease prognosis. Herein, a novel type of immunoassay was developed for detection of cancer biomarkers, using alpha-fetoprotein (AFP) and mucin-16 (MUC16) as model analytes. Using gold nanoparticle (AuNP) bioconjugates as a signal production tool, relevant antibody (Ab)-conjugated AuNPs were prepared on the nitrocellulose (NC) membrane. To construct a spot-like point-of-care (POC) immunoassay, cysteamine conjugated AuNPs (AuNP-Cys) were immobilized on the NC membrane and antibodies were conjugated to the nanoparticle on the detection pad, following a treatment with the samples that contains AFP or MUC16 which are well-known protein biomarkers for liver and ovarian cancer. By using the change in the colorimetric properties of AuNPs, detection of tumor markers was achieved by using a smartphone image and color analysis software at the final stage. Image J application was used for the evaluation of color changes depending on the biomarker concentration in buffer or spiked synthetic serum samples. the linear range was found as 0.1 ng/mL-100 ng/mL for AFP and 0.1-10 ng/mL for MUC16. Limit-of-detection (LOA) was calculated as 1.054 ng/mL and 0.413 ng/mL for AFP and MUC16, respectively. Interferent molecules, Her2, Immunoglobulin G (IgG) and bovine serum albumin (BSA) were tested on the system. Furthermore, synthetic serum samples spiked with selected analyte molecule were applied on the system and measured successfully., COST project of Scientific and Technological Research Council of Turkey (TUBITAK) [117Z609], This work was supported by a COST project of Scientific and Technological Research Council of Turkey (TUBITAK, Project Grant No: 117Z609).

The performance of an amine-based post-combustion CO2 capture and storage (CCS) process in an existing Kraft pulp mill and an existing pulp and board mill was assessed. The pulp and paper industry is an energy-intensive industry, with significant amounts of CO2 emitted onsite. The majority of this CO2 originates from the combustion of biomass, which renders it carbon neutral if the biomass used by the industry is grown and harvested in a sustainable manner. If the CO2 emissions from the pulp and paper industry were to be captured and permanently stored, then this could make the industry a potential carbon sink. In this evaluation, different configurations of capturing CO2 from the flue gases of the recovery boiler, the multi-fuel boiler and the lime kiln were assessed. For a stand-alone Kraft pulp mill, the excess steam available is sufficient to cover the demand from the CO2 capture plant. For an integrated pulp and board mill, there is less excess steam available for the CO2 capture plant and an auxiliary boiler may be required. The retrofit of a post-combustion CO2 capture plant into an existing pulp mill increases the steam demand by 1-8 GJ/air dried tonne (adt) pulp, depending on the volume of the flue gas treated. This translates to a reduction in the amount of electricity exported to the grid by 0.1-1.0 MWh/adt pulp for a stand-alone Kraft pulp mill, and by 0.1-0.5 MWh/adt pulp for an integrated pulp and board mill. The total potential for negative CO2 emissions amounts to just under 2.0 Mt CO2/a both for the market pulp mill and for the integrated pulp and board mill.

In the present manuscript, novel effluent treatment processes for pulp and paper mill effluents are divided into two categories: a) those involving the use of chemical additives and b) those which are free of such chemicals. It is especially of high importance for pulp and paper industry to adopt the most efficient and cost-effective treatment methods. This paper critically reviews the recent studies on the treatment of pulp and paper mill effluents while providing suggestions for further studies on the application of various physic-chemical and biological methods for the treatment of such complex effluents containing a number of recalcitrant pollutants. Keywords: Pulp and paper industry, Industrial effluents, Chemical additives, Non-additive treatment processes

This work is concerned with the electrochemical detection of new psychoactive substances (NPSs), in particular 2,5-dimethoxy-N-(2-methoxybenzyl) phenethylamine structures (NBOMes) and the analogous 2,5-dimethoxy phenethylamine structures (2C-X group) on boron-doped diamond (BDD) electrodes. Fast square-wave voltammetry was used to identify the substances in question. The antifouling properties of the BDD surface resulted in stable, repeatable, sensitive and unique voltammetric responses for these NPSs, producing different voltammetric signatures. Different NBOMes were identified by voltammetric methods in blotting paper seized from the drug market, without any interference from LSD, another psychedelic drug distributed via blotting paper. The proposed method achieved detection limits lower than 0.1μmolL−1 with high precision (RSD

We have previously reported that crystalline samples of 1-acetylaminopyrene (AAPy), 1-octanoylaminopyrene (OAPy), and 1-stearoylaminopyrene (SAPy) exhibited mechanochromic luminescence. In the present study, we have found that these 1-alkanoylaminopyrenes adsorbed onto cellulose papers also exhibited mechanochromic luminescence; however, their behaviors were essentially different from those observed for their crystalline samples. In addition, these cellulose papers were found to exhibit reversible emission color change upon alternate exposure to ethanol and water vapors. It was suggested that 1-alkanoylaminopyrene molecules were dispersed in the paper without aggregation or crystallization and that intermolecular distance of 1-alkanoylaminopyrenes in the paper was reduced by either mechanical stress or exposure to ethanol vapor, resulting in increasing the sites where excimers could be formed and/or in enhancing the efficiencies of energy migration to reach the excimer sites.

Through design hierarchical architectures and interlayer interaction, multifunctional macroscopic graphene oxide papers tend to attain outstanding mechanical properties. Three dimensional architectures functionalized graphene oxide papers are self-assembled with zirconium diboride particles and poly(vinyl alcohol, PVA) using vacuum assisted filtration method. Firstly, ternary graphene oxide micro-scale structures are achieved by the addition of zirconium diboride particles. Then, PVA is introduced to enhance the interface interaction between graphene oxide nanosheets and zirconium diboride particles. The results show significant enhancements in fracture strength (~200%) and tensile modulus (20–100%) are attained through synergistic effect of ternary graphene oxide structures and interlayer interaction between PVA, graphene oxide and zirconium diboride particles. Keywords: Graphene oxide paper, Zirconium diboride, Mechanical behaviors

The deposition of chemical reagent inks on paper is a crucial step in the development and fabrication of microfluidic paper-based analytical devices (mu PADs). A pen-plotting approach, delivering chemical ink deposition using technical pens filled with reagents and inserted into a desktop electronic plotter, is shown herein to be a versatile, low-cost, simple, rapid, reproducible, and high-throughput solution. The volume of the deposited ink was quantified gravimetrically, confirming that nanoliter volumes of reagents can be deposited reproducibly (e.g. 7.55 +/- 0.37 nL/mm for a plotting speed of 10 cm/s) in detection zones of mu PADs, typically spatially defined using wax printing. This approach was further investigated with regard to deposition of reagents in different geometrical forms (circular and linear), so demonstrating its applicability for preparation of mu PADs with flexible design and application. By adjusting the plotting speed for linear deposition, lines with a relatively large range of widths (approximate to 628-1192 mm) were created. Circular deposition was also demonstrated via delivery of reagents within wax printed circular fluidic barriers of a range of diameters (inner diameter = 1.5-7 mm). These capabilities were practically demonstrated via the fabrication of mu PADs, based upon differing detection principles for determination of aluminum in natural waters using Morin as the fluorescent reagent. Traditional mu PADs based on digital image colorimetry (DIC) were produced using circular deposition, whilst distance-based mu PADs exploited linear deposition. Both types of mu PADs developed using this method showed excellent precision for determination of trace concentrations of aluminium (average RSDs = 3.38% and 6.45%, and LODs = 0.5 ng (0.25 ppm) and 2 ng (0.5 ppm), for traditional and distance-based detection, respectively).

Lithium-Sulfur (Li-S) batteries are known for their high energy density and cost-effectiveness. However, the Li-S chemistry is a challenging topic due to the shuttle effect and the use of highly reactive lithium metal anode. To solve these issues, ultra-lightweight multilayered graphene coated paper separator is proposed as an interlayer. The interlayer is firstly coated on nickel foil by Chemical Vapor Deposition (CVD) method followed by transferring to the paper by fishing process. By employing this unique technique, a very light (similar to 8 mu g/cm(2)) graphene coating layer is obtained which does not further imply lowering the entire energy density of the cell. As a whole, the cell with graphene coated paper exhibits 610 mAh/g discharge capacity at C/5 after 100 cycles, while the cell without interlayer exhibits much poorer performance. The improved performance is mostly associated with the interaction between graphene and polysulfide species which is proven by X-Ray Photoelectron Spectroscopy measurement as well as the excellent electronic conductivity of graphene layer which behaves as a secondary current collector resulting the cell resistance decrease. (C) 2018 Elsevier B.V. All rights reserved.

This work deals with the mass, energy and exergy analyses of the energy conversion process in a 50 MWth thermal power plant, using residual forest biomass as fuel and integrating bubbling fluidized bed combustion technology. This is a representative case study of the energy production from eucalyptus residual biomass in the Portuguese pulp and paper industry. Analyses are made of the mass, energy and exergy flows, and how they change in the main components of the system, namely the combustion chamber, boiler, drum, superheater, economizer, and combustion air pre-heaters. Sankey and Grassmann diagrams highlight the mass, energy and exergy flows. Special emphasis is given to the energy and exergy efficiencies, which must be based on the useful produced superheated steam to include the influence of the biomass moisture content. The main goal is to find where and what potential exists for energy efficiency improvements. Results show that the main exergy destruction occurs in the combustion process, and that energy and exergy losses are minimal due to the system’s good thermal insulation. Results also show that the main potential for improvement is on the decrease of the residual biomass moisture content.

Understanding the transport processes that occur in carbon-fiber papers (CFPs) used in fuel cells, electrolyzers, and metal-air/redox flow batteries is necessary to help predict cell performance and durability, optimize materials and diagnose problems. The most common technique used to model these thin, heterogeneous, anisotropic porous media is the volume-averaged approximation based on the existence of a representative elementary volume (REV). However, the applicability of the continuum hypothesis to these materials has been questioned many times, and the error incurred in the predictions is yet to be quantified. In this work, the existence of a REV in CFPs is assessed in terms of dry effective transport properties: mass diffusivity, permeability and electrical/thermal conductivity. Multiple sub-samples with different widths and thicknesses are examined by combining the lattice Boltzmann method with X-ray tomography images of four uncompressed CFPs. The results show that a meaningful length scale can be defined in the material plane in the order of 1–2 mm, which is comparable to the rib/channel width used in the aforementioned devices. As for the through-plane direction, no distinctive length scale smaller than the thickness can be identified due to the lack of a well-defined separation between pore and volume-averaged scales in these inherently thin heterogeneous materials. The results also show that the highly porous surface region (amounting up to 20% of the thickness) significantly reduces the through-plane electrical/thermal conductivity. Overall, good agreement is found with previous experimental data of virtually uncompressed CFPs when approximately the full thickness is considered. The authors thank the support team of Calcul Quebec and Compute Canada for their help during the simulation campaign, as well as Dr. Dula Parkinson and Dr. Alastair MacDowell at the Advanced Light Source (ALS) for help in obtaining the tomographic images. This work was funded under the Fuel Cell Performance and Durability Consortium (FC-PAD), by the Fuel Cell Technologies Office (FCTO), Office of Energy Efficiency and Renewable Energy (EERE), of the U.S. Department of Energy under contract number DE-AC02-05CH11231, Project ENE2015-68703-C2-1-R (MINECO/FEDER, UE) and the research grant 'Ayudas a la Investigation en Energia y Medio Ambiente' awarded to the first author by the Spanish lberdrola Foundation. I.V. Zenyuk and A.D. Shum would like to acknowledge support from the National Science Foundation under CBET Award 1605159. X-ray tomography experiments were performed on beamline 8.3.2 at the ALS (Lawrence Berkeley National Laboratory), which is a national user facility funded by the Department of Energy, Office of Basic Energy Sciences under contract DE-ACO2-05CH11231. Numerical calculations were performed on the supercomputing clusters Briaree, Colosse, Guillimin and Mp2, managed by Calcul Quebec and Compute Canada. The operation of these supercomputers is funded by the Canada Foundation for Innovation (CFI), Ministere de l'Economie, de l'Innovation et des Exportations du Quebec (MEIE), RMGA and the Fonds de recherche du Quebec -Nature et technologies (FRQ-NT).

Paper mills yield large volumes of sludge materials which pose an environmental and economic challenge for disposal, despite the fact that they could be a valuable source for cellulose nanofibres (CNF) production. The aim of the study was to evaluate the production process and properties of CNF prepared by mechanical fibrillation of never-dried and dried paper mill sludge (PMS). Atomic force microscopy (AFM) showed that average diameters for both never-dried and dried paper sludge nanofibres (PSNF) were less than 50 nm. The never-dried and dried sludge nanofibres showed no statistical significant difference (p>0.05) in strength ∼92 MPa, and ∼85 MPa and modulus ∼11 GPa and ∼10 GPa. The study concludes that paper mill sludge can be used in a dried state for CNF production to reduce transportation and storage challenges posed on industrial scale.

The use of fibre-based materials as substrates in printed electronics has been increasing, mainly due to its attractive characteristics, such as low-cost or wide availability. Additionally, paper enables recycling and it shows attractive features, such as high thermal stability, when compared to traditional polymer-based substrates (Tobjörk and Österbacka, 2011 [1]). Nevertheless, one of the drawbacks of using paper substrates is that the surface usually is very rough, typically, showing roughness values above 10 μm2. In most cases, printing structures that need to be highly uniform, without disruptions, require additional coating. Inkjet printing provides sharp detail reproduction and strict lines on printed structures. Sintering is required for drying the ink. Thermal sintering is the traditionally used method, but requires long periods of time and promotes the ageing of the paper due to a long exposure at high temperature. When printing conductive structures on paper alternative photonic sintering methods such as IR-sintering show some attractive characteristics. IR-sintering is compatible with roll-to-roll fabrication, providing low-cost, fast and localized sintering, which makes it suitable for fibre-based substrates (Tobjörk et al., 2012 [3]). This work has been carried out to study and compare the efficiency of thermal and IR sintering of conductive structures on different paper and polymer substrates. All substrates were printed using silver based ink, which was applied on the substrate surface by inkjet. Resistivity values of the printed structures were used to compare the performance on the substrates. IR-sintering showed the best results in terms of achieved conductivity of the printed lines when using short sintering time of no more than 10 min. The conductivity values of the inkjet-printed silver lines on Lumi silk substrate reached about 40% of the bulk silver value after IR-sintering, whereas with thermal-sintering this value only reached about 20% of the bulk silver value. IR-sintering improves the sintering process, increasing the conductivity of the printed structures and at the same time reducing significantly the sintering time. In the case of Lumi silk substrate, high conductivity was observed after only two minutes of sintering time when IR-oven was used. Both techniques can be used in a roll-to-roll mass manufacturing process, enabling the fabrication in large scale of flexible electronic devices, on paper substrates, without the need for extra steps, such as coatings.

Zeolite nanostructures were used as hosts for dyes normally used in some bioassays (pH and protein), and applied on microfluidic paper-based analytical devices (PADs). The obtained dye nanomaterials were characterized by several techniques (structural (FTIR and XRD), surface (SEM/EDX), textural (N2 adsorption) analyses and dye loading determination by TGA analysis), to confirm the stability of both host and guest. After their deposition on the papers surface, the color change was studied by analyzing the RGB values, taking into account the lifetime and the results stability of the PADs. These results confirmed that both the lifetime and the color change of the modified devices were stable over one week. It was also demonstrated that the choice of the paper for the PAD as well as the zeolite nanostructures properties influences the colorimetric response. This strategy by encapsulating dyes into zeolites solve current challenges in colorimetric sensors in where long-term stability of the colorimetric results is an issue. The results obtained were promising for the studied assays, and the strategy could also be extended to other bioassays., A.R.B. thanks for the ERASMUS+ program to her grant. This work has been developed under the scope of the projects: BioTecNorte (NORTE-01-0145-FEDER-000004), AIProcMat@N2020 (NORTE-01-0145-FEDER-000006), projects supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work also has been funded by ERDF through COMPETE2020–Programa Operacional Competitividade e Internacionalização (POCI), Project POCI-01-0145-FEDER-006984, Associate Laboratory LSRE-LCM and by national funds through FCT, Fundacão para a Ciência e a Tecnologia for project PTDC/AAGTEC/5269/2014 and Centre of Chemistry (UID/QUI/00686/2013 and UID/QUI/0686/2016). The support from the Oslofjordfondet project, «Touchsensor for enklere og raskere urinprøvetaking og analyse (no. 234972)» and NSFC project no. 61650410655 is also acknowledged., info:eu-repo/semantics/publishedVersion

The economics of Recycled Paper Sludge conversion into ethanol was here assessed with emphasis on integrating a cellulase recycling system. Without cellulases recycling this process presented positive economic outputs (payback period of 7.85 years; 10.90 Million US$ of accumulated NPV) despite the modest ethanol titers. Recycling both free and solid-bound enzymes allowed considerable savings of enzyme but also an increase on annual costs (0.88 %), resulting on a superior economic output: payback period decreased to 7.25 years; accumulated NPV increased to 14.44 Million US$. Recycling exclusively the liquid fraction enabled a clear costs reduction, however, also total ethanol decreased, attenuating the abovementioned benefits. Targeting higher ethanol concentrations, superior solids consistencies were also evaluated. Despite a costs reduction, total ethanol decreased due to a higher ethanol retention on the solid. A sensitivity analysis further revealed that the cost of enzymes and ultrafiltration membrane may be critical on enzyme recycling economic feasibility., This work had the financial support of the Portuguese Foundation for Science and Technology, Portugal (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the MultiBiorefinery project (POCI-01-0145-FEDER-016403). Furthermore, FCT equally supported the PhD grant to DG (SFRH/BD/88623/2012)., info:eu-repo/semantics/publishedVersion

For the first time the feasibility of using an alkaline wastewater coming from the pulp and paper industry as an activator, partially (50 vol%) replacing commercial sodium hydroxide, in the production of cork-based activated carbons was evaluated. The activated carbons showed the highest value of specific surface area ever reported for cork-based activated carbons (1670 m2/g), surpassing several other commercial and waste-based ones. These eco-friendly cork and paper waste-based activated carbons were then evaluated as methylene blue adsorbent materials. The influence of contact time, methylene blue initial concentration and adsorbent amount on the methylene blue removal efficiency by the activated carbons was studied. Extremely fast (>99.9% removal in 5 min) and efficient methylene blue adsorption (uptake of 350 mg/g) by the cork and paper waste-based adsorbents was achieved, which demonstrates the huge potential of these innovative adsorbents. These activated carbons were produced using two unexplored industrial by-products (alkaline wastewater and cork) and, therefore, may be an inexpensive source of activated carbons, which can be used for the effective removal of dyes from wastewaters. Furthermore, despite the very large surface area and high removal efficiency this is not a nano material (being around 30–50 μm in size), its capabilities being due to its unique cork-derived microstructure, and hence it can be handled and removed/filtered much more easily than nanocarbons, and without any associated health or environmental risks. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. R.C. Pullar wishes to thank FCT grant IF/00681/2015 for supporting this work, and R.M. Novais wishes to thank FCT project H2CORK (PTDC/CTM-ENE/6762/ 2014). published

An overview of the last trends in lab-on-chip technology highlights the continuous development of biosensing approaches in terms of simplicity, low-cost, and quick response, with a higher sensitivity and selectivity. In this context, electrochemical sensors arrived to overcome the need to develop small, accurate, portable and compact sensing devices, compatible with routine use in loco analysis, especially in point-of-care (POC) assessment. Herein, we have presented the first paper-based electrochemical sensor towards the detection of 3-nitrotyrosine (3-NT), a relevant oxidative stress biomarker. This innovative sensor was designed by, first, modifying paper to become a hydrophobic support and, second applying carbon and silver conductive inks to generate a three electrode-system on a small spot. An intensive voltammetric investigation of the paper-based screen-printed electrodes (SPEs), including the study of different redox-probes, scan-rate values, probe concentrations and supporting electrolyte solutions, confirmed their suitable and reliable electrochemical performance. Square wave voltammetry (SWV) was employed to assess the sensitivity of the proposed sensor at various concentrations of 3-NT, ranging from 500nM to 1mM, enabling a low detection limit (LOD) of 49.2nM. The interference of co-existing species was also tested and good selectivity against 3-NT was accomplished. Overall, this flexible paper-based platform constitutes a promising sensor material towards a quick, sensitive, cost-effective, sustainable and reproducible detection of 3-NT biomarker., European Research Council (ERC) is acknowledged for funding this work through the Starting Grant 3P's (ERC/StG/3P's/GA311086). Portuguese Foundation for Science and Technology (FCT) also supported this work through FEDER funds from COMPETE 2020 Program and National Funds, under the project UID/CTM/50025/2013 and the PhD Grants references SFRH/BD/94159/2013 (GVM) and SFRH/BD/115173/2016 (ACM)., info:eu-repo/semantics/publishedVersion

In the paper, the impact of paper production waste (primary sludge, or PS) on the properties of cement pastes and mortars is discussed upon. Some specimens were formed with fine PS fraction that replaced a part of cement content in them (5%, 10%, 15%, or 20%); in other specimens, coarse fraction of sludge (2/4) was used and a part of content of fine filler (sand) was replaced by PS. The properties of mixtures, such as water content required for cement paste of normal consistence, the setting time, exothermic temperature, flow diameter and plunger penetration, were established. In addition, the properties of hardened mortar, such as its density, flexural strength and compressive strength, were established. The microstructure of hardened specimens was examined as well. It was found that PS retarded hydration processes and reduced exothermic temperature; in addition, it reduced the flow diameter and the plunger penetration. While assessing the properties of hardened mortar, it may be stated that 5% PS waste might be used for replacement of a part of cement content.

Herein, we report a first example of a rapid and easy to use paper-based printed sensor embedded in a 3D printing device to measure the butyrylcholinesterase activity in serum samples. The innovative device relies on a paper-based sensor fabricated using wax printing and screen-printing technologies, combined with a printed holder made by stereolithography using 3D printing technology. To measure the butyrylcholinesterase activity, butyrylthiocholine was used as enzymatic substrate and the by-product thiocholine was detected with a paper-based electrochemical sensor modified with a Carbon Black and Prussian Blue nanocomposite. The presence of this nanocomposite allowed to perform the butyrylcholinesterase activity measurement at low applied potential (+300 mV vs. Ag/AgCl pseudoreference), since it is able to electrocatalyse the thiocholine oxidation, overcoming the fouling problem occurring at a bare electrode. To obtain a “reagent free” sensor, butyrylthiocholine was loaded on the filter paper for a reliable stand-alone measurement, requiring only the sample addition. This device, after the calibration with standard solutions, was tested in serum samples, achieving a linear range up to 12 UI/mL and a detection limit of 0.5 IU/mL. To evaluate the accuracy of the device, recovery studies were performed in serum samples, demonstrating the suitability as a point of care for screening analysis of BChE activity measurement, taking into account that the normal value range is comprised between 5.9 and 13.2 IU/mL.

Electron beam lithography (EBL) was used for preparing nanostructured reduced patterns on the GO paper surface, while preserving its mechanical resistance and flexibility. Different EBL parameters, like dose and time of exposure for patterning were tested. SEM analysis showed the consequent increase of contrast of the reduced stripes on the patterned regions due to the increase of electron beam doses. Moreover, surface potential microscopy experiments also exhibited a clear contrast between the patterned and non-patterned regions. Structural analysis of the patterned paper through X-ray diffraction and nanoindentation showed that the interlayer distance between GO sheets decreases after reduction allowing the increase of the Hardness and Young modulus that makes this material able to be manipulated and integrated on different devices. Furthermore, we also observe that exposed areas to electron beam reduction process show an increase in the electrical conductivity up to 3 × 104 times. The developed flexible GO films can have interesting applications such as biosensors or templates for inducing tissue regeneration, by providing a surface with differently patterned cues with contrasting electron mobility. Preliminary in vitro studies with L929 fibroblasts support the cytocompatible nature of this patterned GO paper., Gil Gonçalves thanks the Fundação para a Ciência e a Tecnologia for the PostDoc grant (SFRH/BDP/84419/2012). P.A.A.P.M. acknowledge the FCT/MCTES for a research contract under the Program Investigator 2013 (IF/00917/2013/CP1162/CT0016) and TEMA – Centre for Mechanical Technology and Automation (UID/EMS/00481/2013), financed by national funds through the FCT/MEC. I.B. wish to acknowledge the Portuguese Foundation for Science and Technology for the financial support (grant IF/00582/2015). H·I·S.N. acknowledges CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. The biological studies of this work have been funded by the Ministerio de Economía y Competitividad and the Fondo Europeo de Desarrollo Regional (MAT2016-78857-R, MINECO/FEDER, UE). AGM and MCS acknowledge ISCIII-MINECO-FEDER for respective contracts. Authors would like to thank Dr M. Teresa Portolés from the Biochemistry and Molecular Biology Department at Universidad Complutense de Madrid for the generous supply of L929 fibroblasts. Dr José Ángel Rodríguez and Dr Javier Mazarío from the Service of Microscopy and Image Analysis at the Hospital Nacional de Parapléjicos are acknowledged for assistance with CLSM studies and Dr Enrique Rodríguez from the Servicio Interdepartamental de Investigación at the Universidad Autónoma de Madrid for SEM studies., info:eu-repo/semantics/acceptedVersion

As two important industrial manufacturing materials, ceramics and metals have their own advantages and disadvantages in terms of physical, chemical, and mechanical properties. The field of material manufacturing has witnessed efforts to develop technical processes that can properly combine these two alloys, aiming to effectively use their respective advantages. The welding technology for ceramics and metals, as a research topic with broad prospects, is comprehensively and deeply analyzed in this review. The current research progress in this field is analyzed from different process perspectives such as fusion welding, brazing welding, diffusion welding. By using appropriate intermediate materials between these two materials, the residual stress and brittle intermetallics near the interface of the transition joint can be minimised by solving the thermal expansion mismatch, reducing the bonding temperature and pressure.

© 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/, Hydration of a multi-layered graphene oxide (GO) paper in water vapor atmosphere was studied by in-situ X-ray scattering over a wide range of relative humidity (RH). The intercalation of water molecules physically adsorbed between GO layers induces the expansion of the interlayer distance. Two regimes of adsorption are clearly evidenced according to the variation of the interlayer distance as a function of the relative humidity. The expansion of the interlayer distance is limited to ∼1 Å for RH ranging from 6 to 53%, whereas it is ∼3.5 Å for RH 75–100%. The hydration mechanism corresponds to the progressive adsorption of water molecules onto hydrophilic sites at the surface of GO layers in the low-RH regime, then an additional water monolayer is formed in the high-RH regime., EP, SR and PL benefited of a grant from the French Research National Agency under the program Investissements d’Avenir (SEDECO project, ANR-10-LABX-0035: Labex NanoSaclay). AMB and WKM acknowledge funding from the Spanish MINEICO (project ENE2016-79282-C5-1-R), the Gobierno de Aragón (Grupo Reconocido TO3_17R) and associated EU Regional Development Funds.

In this paper, we study how to fold a specified origami crease pattern in order to minimize the impact of paper thickness. Specifically, origami designs are often expressed by a mountain-valley pattern (plane graph of creases with relative fold orientations), but in general this specification is consistent with exponentially many possible folded states. We analyze the complexity of finding the best consistent folded state according to twometrics:minimizing the total number of layers in the folded state (so that a “flat folding” is indeed close toflat), andminimizing the total amount of paper required to execute the folding (where “thicker” creases consume more paper). We prove both problems strongly NP-complete even for 1D folding. On the other hand, we prove the first problem fixed-parameter tractable in 1D with respect to the number of layers., National Science Foundation (U.S.). Origami Design for Integration of Self-assembling Systems for Engineering Innovation (grant EFRI- 124038), National Science Foundation (U.S.). Expedition grant (CCF-1138967), United States. Department of Defense. National Defense Science and Engineering Graduate (NDSEG) Fellowship (32 CFR 168a)

This study focused on preparation of microfibers from bamboo culms using steam explosion with and without chemical treatments, and utilization of the isolated fibers in formation of bamboo paper fabricated with nanofibrillated cellulose (NFC). Compared with those obtained from the steam explosion alone (S), the bamboo microfibers isolated using the steam explosion followed by bleaching process (S/A) exhibited a significantly reduced fiber width of 7.5 μm and a markedly increased cellulose content of 97.85%. The S/A fiber showed an increased decomposition temperature, corresponding with lower contents of hemicellulose and lignin than those of the S fiber. The S/A microfibers were subsequently proceeded to paper formation. Physical and mechanical properties of the paper with an introduction of different NFC concentrations (0–50 wt%) were investigated. The linear relationship between the density, porosity and mechanical properties of the paper and NFC contents was observed. The more the NFC content, the greater the density and the lower the porosity the paper exhibited. At 50 wt% NFC, the paper density increased to 0.64 g cm−3, and the paper porosity decreased to 57.0% whereas the paper without NFC showed a density of 0.39 g cm−3 and porosity of 73.6%. Tensile strength and strain of the paper composed with 50 wt% NFC were 10-fold and 3-fold, respectively, greater than those of the paper without NFC. The addition of NFC could manifest paper mechanical properties and porosity within the paper structure, which would be useful for scaffold and membrane applications. Keywords: Bamboo, Mechanical properties, Paper, Nanofibrillated cellulose, Steam explosion, Microfibers, Nanofibers

Background: There is a pressing need for effective education to help develop basic research and publication skills among clinicians in low and middle-income countries (LMIC). Learning from experience is important for achieving understanding of concepts and acquisition of skills rather than simply recall of facts. Methods: An innovative research and academic writing skills course was run for 21 participants from two universities in the Philippines. The experientially-based workshop encouraged development of skills and understanding through active involvement. Interaction with tutors and other participants was integral to the process. The novel workshop design linked various phases of the research process to relevant sections of an academic paper, thus integrating activities usually regarded as separate.This paper outlines the structure of the workshop and reports its evaluation through pre- and post-workshop surveys and post-workshop focus groups. Results: Participants appreciated the integrated format of the workshop and felt more confident in their ability to plan, conduct and write up research. Conclusion: Explicitly linking elements of an academic journal article to the components of developing a research project was successful in promoting learning and understanding of the research process and increased confidence in academic writing in this context and is likely transferable to similar contexts. Keywords: Research skills, Writing skills, Integrated workshop, Learning

We present a computational framework for stability analysis of systems of coupled linear Partial-Differential Equations (PDEs). The class of PDE systems considered in this paper includes parabolic, elliptic and hyperbolic systems with Dirichlet, Neuman and mixed boundary conditions. The results in this paper apply to systems with a single spatial variable. We exploit a new concept of state for PDE systems which allows us to include the boundary conditions directly in the dynamics of the PDE. The resulting algorithms are implemented in Matlab, tested on several motivating and illustrative examples, and the codes have been posted online. Numerical testing indicates the approach has little or no conservatism for a large class of systems and can analyze systems of up to 20 coupled PDEs.

Pulp and paper industry produces massive amounts of sludge from wastewater treatment, which constitute an enormous environmental challenge. A possible management option is the conversion of sludge into carbon-based adsorbents to be applied in water remediation. For such utilization it is important to investigate if sludge is a consistent raw material originating reproducible final materials (either over time or from different manufacturing processes), which is the main goal of this work. For that purpose, different primary (PS) and biological sludge (BS) batches from two factories with different operation modes were sampled and subjected to pyrolysis (P materials) and to pyrolysis followed by acid washing (PW materials). All the materials were characterized by proximate analysis, total organic carbon (TOC) and inorganic carbon (IC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and N2 adsorption isotherms (specific surface area (SBET)and porosity determination). Sludge from the two factories proved to have distinct physicochemical properties, mainly in what concerns IC. After pyrolysis, the washing step was essential to reduce IC and to considerably increase SBET, yet with high impact in the final production yield. Among the materials here produced, PW materials from PS were those having the highest SBET values (387-488 m2 g-1). Overall, it was found that precursors from different factories might originate final materials with distinct characteristics, being essential to take into account this source of variability when considering paper mill sludge as a raw material. Nevertheless, for PS, low variability was found between batches, which points out to the reliability of such residues to be used as precursors of carbon adsorbents. L'Oreal Portugal published

This work addresses the development of a compact paper-based enzymatic microfluidic glucose/O2 fuel cell that can operate using a very limited sample volume (≈35 µl) and explores the energy generated by glucose at concentrations typically found in blood samples at physiological conditions (pH 7.4). Carbon paper electrodes combined with a paper sample absorption substrate all contained within a plastic microfluidic casing are used to construct the paper-based fuel cell. The anode catalysts consist of glucose dehydrogenase and [Os(4,4′-dimethoxy-2,2′-bipyridine)2(poly-vinylimidazole)10Cl]+ as mediator, while the cathode catalysts were bilirubin oxidase and [Os(2,2′-bipyridine)2(poly-vinylimidazole)10Cl]+ as mediator. The fuel cell delivered a linear power output response to glucose over the range of 2.5–30 mM, with power densities ranging from 20 to 90 µW cm−2. The quantification of the available electrical power as well as the energy density extracted from small synthetic samples allows planning potential uses of this energy to power different sensors and analysis devices in a wide variety of in-vitro applications., Peter Ó Conghaile is thanked for synthesis of the redox polymers. Neus Sabaté acknowledges funding from the European H2020 Framework Programme (Grant Agreement 648518 - SUPERCELL - ERC 2014 CoG). Juan Pablo Esquivel would like to thank the support from Marie Curie International Outgoing Fellowship (APPOCS) within the 7th European Community Framework Programme. F. Javier del Campo acknowledges funding from the Spanish Ministry of Economy through the DADDi2 project (TEC2013-48506-C3). Dónal Leech acknowledges support from Grant number 607793 under the Bioenergy FP7-PEOPLE-2013-ITN Programme.

Over the past few years, what might not unreasonably be described as a true revolution has taken place in the field of machine vision, radically altering the way many things had previously been done and offering new and exciting opportunities for those able to quickly embrace and master the new techniques. Rapid developments in machine learning, largely enabled by faster GPU-equipped computing hardware, has facilitated an explosion of machine vision applications into hitherto extremely challenging or, in many cases, previously impossible to automate industrial tasks. Together with developments towards an internet of things and the availability of big data, these form key components of what many consider to be the fourth industrial revolution. This transformation has dramatically improved the efficacy of some existing machine vision activities, such as in manufacturing (e.g. inspection for quality control and quality assurance), security (e.g. facial biometrics) and in medicine (e.g. detecting cancers), while in other cases has opened up completely new areas of use, such as in agriculture and construction (as well as in the existing domains of manufacturing and medicine). Here we will explore the history and nature of this change, what underlies it, what enables it, and the impact it has had - the latter by reviewing several recent indicative applications described in the research literature. We will also consider the continuing role that traditional or classical machine vision might still play. Finally, the key future challenges and developing opportunities in machine vision will also be discussed.

A simple field method for determination of fluoride in drinking water using handmade fluoride reagent paper impregnated by aluminium quinalizarin complex was developed. Fluoride reacts with the impregnated reagent paper to release the free ligand with new colour, orange different from that of the complex. The change in the colour, which is proportional to the amount of fluoride, was measured by the Arsenator. The functionality of the Arsenator which is based on a photometric measurement of spot on the reagent paper is expanded to analyse fluoride. The method allows a reliable determination of fluoride in the range 0.0–2.0 mg L−1. Further spectrophotometric determinations of fluoride showed that Beer’s law is obeyed in the range of 0.3–5.0 mg L−1 at 553 nm. Sensitivity, detection limit, quantitation limit, and the percentage recovery of 1.5 mg L−1 fluoride were found to be 0.117 μg mL−1, 0.1 mg L−1, 0.3 mg L−1, and 101.2 respectively.

Microfluidic paper-based analytical devices (microPADs) are a relatively new group of analytical tools thatrepresent an innovative low-cost platform technology for fluid handling and analysis. Nonetheless, microPADs lack in the effective handling and controlling of fluids, which leads to a main drawback for their reproducibility in large volumes during manufacturing, their transition from the laboratory into the marketand thus accessibility by end-users. Herein we investigate the applicability of ionogel materials basedon a poly(N-isopropylacrylamide) gel with the 1-ethyl 3-methylimidazolium ethyl sulfate ionic liquidas fluid flow manipulator in microPADs using the ionogel as a negative passive pump to control the flowdirection in the device. A big challenge undertook by this contribution is the integration of the ionogel materials into the microPADs. Finally, the characterisation and the performance of the ionogel as a negative passive pump is demonstrated. The project was carried out with the support of the Ramón y Cajal programme (Ministerio de Economía y Competitividad). FBL thanks to the European Union’s Seventh Framework Programme(FP7) for Research, Technological Development and Demonstration under grant agreement no. 604241 and the Gobierno Vasco, Dpto. Industria, Innovación, Comercio y Turismo under ELKARTEKKK-2015/00088. FBL and TA personally acknowledge Marian M.de Pancorbo for letting them to use her laboratory facilities at UPV/EHU. MCMM acknowledges the Basque Government under theEtortek Program (Grant No. IE14-391) and Dr Seifert for the use ofhis laboratory facilities. NG-G work was supported by a PhD fellowship from the University of Navarra. Authors also acknowledge Adhesive Research for the donation of the PSA samples.

This work demonstrates a stand-alone power source that integrates a paper-based hydrogen fuel cell with a customized chemical heater that produces hydrogen in-situ upon the addition of a liquid. The presented approach operates by capillary action and takes advantage of the hydrogen released as a by-product of an exothermic reaction used in point-of-care diagnostics. The paper-based fuel cell produces a maximum power of 25.8 mW (103.2 mW cm−2), which is suitable for powering a diversity of electrical devices such as commercially available digital pregnancy tests and glucometers. While device shape and dimensions can be customized, here it is shown that the fuel cell can be designed in a compact form factor and footprint comparable to a lateral flow test while providing a remarkable power output. This approach holds great promise for powering portable diagnostics, as the generated electric power could enable device functionalities required for advanced assays, such as device timing, actuation, and signal quantification. Part of the same liquid sample that is to be analyzed (urine, saliva, water, etc) could be used to trigger the hydrogen generation and start the fuel cell operation., J.P. Esquivel acknowledges support from Marie Curie International Outgoing Fellowship (APPOCS - GA.328144) within the 7th European Community Framework Programme. J. Buser and P. Yager were supported by a grant from DARPA DSO/BTO--HR0011-11-2-0007, awarded to Yager at the University of Washington. P. Yager was supported in part by funds from the Department of Bioengineering at the University of Washington. S. Rojas acknowledges financial support from project ENE2013-42322R. N. Sabaté would like to thank financial support received from ERC Consolidator Grant (SUPERCELL - GA.648518).

In this work, several cellulose board grades, including waste board, fluting, and waste milk container board, were pretreated with green choline chloride-urea deep eutectic solvent (DES) and nanofibrillated using a Masuko grinder. DES-treated bleached chemical birch pulp, NaOH-swollen waste board, and bleached chemical birch pulp were used as reference materials. The properties of the nanofibrils after disc grinding were compared with those obtained through microfluidization. Overall, the choline chloride-urea DES pretreatment significantly enhanced the nanofibrillation of the board pulps in both nanofibrillation methods—as compared with NaOH-treated pulps—and resulted in fine and long individual nanofibrils and some larger nanofibril bunches, as determined by field emission scanning electron microscopy and transmission electron microscopy. The nanofibril suspensions obtained from the DES pretreatment had a viscous, gel-like appearance with shear thinning behavior. The nanofibrils maintained their initial crystalline structure with a crystallinity index of 61%–47%. Improved board handsheet properties also showed that DES-treated and Masuko-ground waste board and paper nanocellulose can potentially enhance the strength of the board. Consequently, the DES chemical pretreatment appears to be a promising route to obtain cellulose nanofibrils from waste board and paper.

An organometallic dye, europium tetrakis dibenzoylmethide triethylammonium (EuD4TEA) and gold nanoparticles (Au NPs) impregnated paper based sensor platform have been utilized for development of fluorescence turn-on cyanide assay in aqueous media. The ordinary filter paper with 6 μ m pore size were employed as solid support that facilitates impregnation of EuD4TEA and gold nanoparticles and provides durability. Detection mechanism relying on two processes (i) dissolution of gold nanoparticles causing fluorescence recovery and (ii) ligand exchange of triethyl amine with CN group stimulating cyanide specific fluorescence enhancement. The paper platform exhibit naked eye distinguishable color transition upon CN− addition from 10−2 to 10−12 M. To standardize the methodology a homemade image processing algorithm has been developed that enabling calibration of color change and quantify CN− concentration. The described algorithm is applicable to Android smart phones and facilitate transforming these devices into a quantitative cyanide detector. The overall methodology provides instrument free cyanide detection and therefore rapid control of water quality and safety at off-field conditions.

Herein, we describe a sustainable and inexpensive approach to monitor Zn(II) in biological fluids by fabricating an office paper-based electrochemical sensor. By following two easy steps, consisting of wax patterning and electrode screen-printing, the office paper provides an effective electroanalytical tool that is easily extensible to a broad range of analytes. This approach would be able to develop affordable user-friendly sensing devices, tackling the lack of resources in regions with poor-settings/facilities. In order to provide more details regarding the screen-printed electrodes fabrication, office paper, Whatman #1 chromatrographic paper, and polyester have been characterized with electrochemical, morphological, and mechanical tests and compared. Using office paper, Zn(II) has been detected linearly up to 2 μg/mL with a detection limit equal to 25 ng/mL and a relative standard deviation of 8%. To highlight the feasibility, reliability, and easiness of the proposed electrochemical sensor, Zn(II) has been detected in serum and sweat at physiological level (μg/mL), and the accuracy of the method has been verified by satisfactory recoveries close to 100%.